EME on Android: Improve accuracy of Key System availability.

media/base/media.cc

Index: media/base/media.cc
diff --git a/media/base/media.cc b/media/base/media.cc
index efc495b682e3150fd0d40496d5859e13d5dc5d82..b2e1c4520174e7a04fb50c393dd3c32646700d2d 100644
--- a/media/base/media.cc
+++ b/media/base/media.cc
@@ -115,6 +115,12 @@ bool IsUnifiedMediaPipelineEnabledForMse() {
              switches::kEnableUnifiedMediaPipeline) ||
          !MediaCodecUtil::IsMediaCodecAvailable();
 }
+
+bool ArePlatformDecodersAvailable() {
+  return IsUnifiedMediaPipelineEnabled()
+             ? HasPlatformDecoderSupport()
+             : MediaCodecUtil::IsMediaCodecAvailable();
+}
 #endif
 
 }  // namespace media